DEFINITIONS
Light transmission (LT)

Luminous beam transmitted through the glass in relation to the incident light beam expressed by the radiation CIE D65 whose spectral density goes from 380 nm to 780 nm. The percentage of light that reaches the premises through the glazing. It is expressed as a percentage.

Light reflection (RI)

The amount of visible light reflected by the glazing. It is expressed as a percentage.

Energy transmission (Ted)

Part of the solar energy that is transmitted through the glass and whose spectral density goes from 300 to 2150 nm. It is expressed as a percentage.

Energy reflection (Re)

Part of the solar energy reflected by the glazing. It is expressed as a percentage.

Energy absorption (Ae)

The amount of solar energy absorbed by the glass that makes the glazing. It is expressed as a percentage.

Solar factor (g)

This value expresses the thermal energy that penetrates into premises through solar radiation. According to standard UNE-EN-410, this value is made up of two factors, the radiant energy from the sun that enters the premises by direct transmission through the glazing and the energy that this cedes as thermal energy inside the premises after having been absorbed by the glazing and having produced its reheating. The lesser the g value is, the better the protection against reheating is.

Thermal insulation coefficient U

The amount of heat per hour (expressed in watts) transmitted through a surface area of 1 m2 per each Kelvin degree of difference between the interior and the exterior. This coefficient is expressed as W/m2K. The lesser the U value, the better the thermal insulation is and less energy dissipates through the glazing.